A programmable microprocessor, such as a digital signal processor, may handle events such as interrupts and exceptions. An interrupt may be an event which changes the normal instruction flow in the processor. An exception may be a software-initiated event which arises when an error is encountered, such as an invalid instruction or bus error.
Interrupts may be nested. For example, a second interrupt (e.g., a nested interrupt) may be received while a first interrupt is still being handled. Thus, at any given time, a number of interrupt service routines may be active. A prioritization scheme may be used to deal with multiple active service routines in an efficient manner.